


Fooling Around

by UselessPileOfStressAndSadness



Category: Marvel Cinematic Universe, The Avengers (Marvel Movies), The Avengers (Marvel) - All Media Types
Genre: F/M
Language: English
Status: Completed
Published: 2019-05-31
Updated: 2019-05-31
Packaged: 2020-04-05 02:30:12
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 5,023
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19039345
Author URL: https://archiveofourown.org/users/UselessPileOfStressAndSadness/pseuds/UselessPileOfStressAndSadness
Summary: (Y/N) has the ability to heal any wound, even death, and she has been hunted by the Avengers for years, being considered a liability if left wandering around (possibly) resurrecting armies. As an assassin, her ability was highly controversial, and when a strange meeting with a tall, handsome, powerful man leaves her wanting more, the most wanted assassin, Black Cross, has been caught and asked to join the Avengers.





	Fooling Around

**Author's Note:**

> The prompt for this piece was "If you’re done fooling around, remove the knife.”

Running across rooftops was such a peaceful activity. (Y/N) was in her assassin’s cloths, which were literally just based off the ninja clothing in movies, but with so many folds and extra pockets for her weapons that she often forgot they were there until she had to empty it for washing. It was sort of inconvenient because it was rather baggy and didn’t provide much protection, but she was faster than light so she’d be fine.

You’d think she’d have memorised all the pockets and gadgets that she busied herself with by now, but no, she hadn’t and it was rather embarrassing when she sometimes has to get caught and patted down to finish an assignment, only to find out she had more hidden pockets than she thought.

She was almost the embodiment of ‘put all your weapons down - *pulls out more weapons than humanly possible*’.

She jumped and sailed through the air, a shadow against the full moon in the sky. The only defining feature on her body, was the white outline of a black version of the Red Cross on her back, and a smaller version on her forehead.

Which is where she got her name, the Black Cross.

Tonight’s assignment: Tony Stark. Honestly, he had appeared on his list multiple times, and every time she went for observation, he didn’t show any of the psychopathic symptoms the women who reported him to have. She even observed him have a panic attack in his own workshop.

All three times she observed him, he was pure-hearted.

She wondered what he did this time for a child to tug at her hand and hand her a slip of paper before slipping away.

Probably a gang that used innocent children as façades. It was honestly annoying, but since no one had reported them to her, she couldn’t do anything to them.

It was a pact she made to herself. Don’t hurt the innocents, and don’t hurt the unreported. She would observe someone for a full 24 hours, sometimes 48 hours, and if they didn’t show any signs of what they were reported for, then she would claim them as innocent.

And she refused to touch anyone who hadn’t been reported because it meant no one was scared enough to go through the effort of contacting a master assassin.

(Y/N) launched herself off the roof of the last house and into the branches of a nearby tree. She didn’t have supernatural strength, or flight, but her supernatural speed, flexibility and senses helped a lot. She also had naturally soft footsteps and a small build from malnutrition early on in her life.

That part wasn’t too fun, and even now, she only just earned enough money to feed herself, water herself and bathe herself at the local pool.

Bouncing tree to tree, without making a sound, she felt something crawl across her skin as the Avengers Compound came into view. It felt like magic.

Her ears were immediately on high alert, and her eyes gained the green tint that meant they had switched to alert, night vision mode.

Inhaling slowly, and deeply, (Y/N) brought in the scent of everything within a 100 kilometre radius.

There was a new person the last time she was here, and whoever they were, they were close.

Pressing herself against the tree, she stilled herself as she heard footsteps.

“He said the trespasser was over on this side!” A male voice called out. Ah, one of the interns. He wasn’t the new scent, but sometimes her senses were off.

Besides, he was perfect, she could knock him and company out, then find a uniform to wear.

Everyone in the vicinity joined him, and before they could spread out, she unzipped a pocket and whilst everyone looked up at her and saw the white cross. A wave of dramatic gasps spread through the crowd, but before anyone could react, she had dropped the sleeping gas bombs on their heads and they were out within seconds.

Jumping down lightly, the grass under her feet barely made a noise, and she paused, one hand on the tree and half her body hidden from the Compound’s view.

She took another deep breath, and the new smell, slightly minty and frosty was closer. Probably 50 metres in front of her, on the clearing near the Compound, but there was nothing there.

Invisibility. The thought came to her immediately.

Shape-shifting. Second idea that the infiltrator had.

Size-changing. They could also have changed their size to that of an ant to be undetectable.

Tilting her head, she used her superb hearing to keep a track of whoever it was. Shape-shifting. It was almost definitely shape-shifting.

A snake.

It was a snake. Of course. She immediately flew up the tree, abandoning her idea to steal someone’s clothes. From her vantage point, she could see a small green viper, around 30 cm long.

A long-nosed whip snake, small, green and very difficult to detect through sound, sight and smell. If you were human, that is.

As soon as the snake reached the edge, it seemed to draw upwards and change into a humanoid in the same, fluid movement.

Very gracefully, the man dusted his black, gold and green ensemble off and glanced upwards, eyes sweeping around until they landed a few trees to (Y/N)’s right.

She slowly, silently drew a two throwing knives. His head whipped around, eyes narrowed at her tree, but she was amply hidden by the leaves. He walked towards the tree, and the knives left (Y/N)’s hands. The first one was let go a split second before the second one, and he smirked as he caught the first one, not seeing the second one until it hit near its intended mark in his chest. Both of them were short enough to keep him relatively unharmed. To be honest, she was aiming for his stomach, but since she couldn’t aim and was lucky that it even landed blade first, she was thankful nonetheless.

She heard him wheeze and jumped down, tucking and rolling, before drawing twin sabre handles, before flicking them open, and approaching the person carefully.

“I suggest you stop right there, child. Your knives are too short, very ineffective against a god.”

“Hm. Loki of Asgard, brother of Thor Odinson, shapeshifter, wielder of the Seidr, god of lies and the one who decided New York was fair game.” (Y/N) said lowly, softly even, as she stalked around him, and he narrowed his eyes. He could see her (E/C) eyes perfectly from his position, especially as she lacked protection there.

He flicked his wrist, and the throwing knife that he had caught flew towards her in almost slow motion, and she swiftly stepped to the side and caught the handle with her super speed, then tucked it away smoothly, before looking back up to see a surprised Loki.

“You know who I am.”

(Y/N) snorted. “Who doesn’t?” She lunged forward, careful not to hurt him too badly, and slashed him across the torso. It tore his leather tunic and created a small, thin cut along his chest.

A second later, twin knives appeared in his hands.

“If you’re done fooling around, remove the knife.” He said calmly, and the temperature dropped by ten degrees, the presence of magic made her skin prickle and she felt her muscles stiffen.

(Y/N) narrowed her eyes. “No offence, but I don’t exactly trust you not to stab me if I get close enough. And why don’t you remove it yourself?”

A crooked smirk spread across his handsome face and he stalked towards her, his knives disappearing, and his scent, his looks, his swagger hit her all at once and she was weak at the knees.

No.

No.

This could not be happening! She screeched in her mind.

First rule of life: don’t get attached.

Second rule of life: don’t fall in love.

Third rule of love: don’t trust anyone.

She backed up slowly, her eyes narrowing and she couldn’t help the blush that crept up her neck as his tunic slowly fell off his shoulders, revealing a rather muscled chest, not muscled like Thor’s, instead, slender with taut muscles.

His pale skin seemed to glow in the night sky, and the devilish smirk was amplified by the angle he held his head at, his prominent cheekbones and the full moon hanging in the sky.

“You don’t want to hurt me.” He stated simply, having backed her against a tree.

“I’m not here for your life.” She flicked her blades back into their handles and hid them in one quick motion, before dancing up the tree and crouching on a branch high above his head.

“You’re the assassin.” Realisation washed over his facial expressions. “I was told, if I ever saw the Black Cross, I was to take them in immediately for multiple charges of murder.”

“369 to be exact.” (Y/N) replied, a smirk playing on her lips as a shiver went up her spine. She had killed 369 people. That was 369 more people that she thought she would kill. That was more people that she had ever healed.

She had even cured cancer once, but she had never cured 369 people.

Loki frowned, and (Y/N) didn’t like it one bit. It marred his beautiful features. He looked almost like a fallen angel. He had the whole ‘dark prince’ thing going on, and it was more attractive than (Y/N) ever thought it could be.

“Then who are you here to kill?”

“It depends.” Was all she said, before she saw the agents starting to wake up. “I really must take my leave now.” She told him simply, and disappeared. She didn’t care much for the throwing knife embedded in his chest, she had plenty others and could always make more of them.

Speeding towards the Compound, across the cleared area around the buildings, she bounced to the top of one of their roofs, completely invisible in the darkness.

She could see Loki marching back to the Compound, a scowl on his face as he repeatedly touched the handle of the blade, before withdrawing his hand as if he had been burnt.

“Dam witches and their stupid purity magic.” He muttered, he was cursing and murmuring to himself, and (Y/N) suddenly realised why he didn’t remove it. Why no one ever removed her weapons from the body.

She had made them herself. Apparently some of her healing ‘magic’ had been put into the blades and now they were untouchable? She had no idea what had happened. Maybe it was her blood? Blood magic? Whenever she made a new weapon, she always dropped a few tears and a few drops of blood on them as a small ritual she made up for fun.

She slipped inside, directly behind Loki, and darted in front of him. Before he could register who she was, or what she was doing, she pulled the blade out of his chest and he gasped as she flicked the blood off it before sheathing it and she stepped closer to him, placing a hand quickly on his chest and reached out with her energy and pushed it into him. His wounds closed, and the second they were gone, she darted down the hallway and into the nearest vents, her flexibility and speed definitely being a plus.

Her hands were shaking. The palm of her hand could still feel his cool, soft skin. He was perfect.

She didn’t need to damage his perfection with her presence any longer.

Shuffling and wriggling, she made her way through the ventilation system, using small squeaks like echolocation to make her way down to Tony’s lab.

She would roost there for a while, and if Hawkeye ended up finding her, she’d just knock him out and dump his body in his room.

She didn’t need her sleeping gas to knock someone out.

 

The two days went up quickly, with two encounters with Hawkeye, the second one slightly messier, and she earned a gash across her eyebrow. Of course her abilities were incredibly annoying, and she couldn’t heal (or take apart) herself, so she was stuck with blood occasionally running into her eye if she left it long enough.

Poking her head out of the original vent she had crawled into, which was also the vent that was closest to the exit, she glanced side to side. She would try to find a way out through the vents, but they were no doubt heavily monitored and probably had fans she didn’t want to tangle with, no matter how fast she could go.

No one there.

Tilting her head to the side and inhaling deeply, she couldn’t scent or hear anything.

Sliding out of the vents, she quickly sprinted towards the door, barrelling straight into an invisible wall.

Invisible wall?

What?

The invisible wall shimmered and revealed a layer of green and black leather. Stepping back, she hit another hard surface. Whipping around, she looked up to see the two Asgardians on the team (even if Loki was only there on probation).

“Oh gods.” (Y/N) cursed violently under her breath as they both looked on almost curiously. “Sorry about this, guys, but it’ll stop when I get out.” She spoke rapidly, faster than they could realise, either of her hands landing on both of their chests, and she pushed a wave of her energy into it, undoing any sort of healing or repairing to their nerves that had ever happened.

They let out silent screams of agony as they crumpled to the ground, every nerve alight and burning as she bent and pulled them apart.

Red lights appeared in the walls, and suddenly, bars started to drop around her.

Sprinting again, she slipped underneath the bars ran towards the door, throwing her arms across her face as she barrelled into the glass.

She fled across the open field, cancelling her abilities tied to the Asgardian brothers early, hoping they’d be too incapacitated, but almost the second she cancelled it, she felt something tighten around her arms, and she was suddenly crushed inwards by two cold hands and the floor disappeared beneath her feet, she was hovering and weightless.

Tesseract-blue eyes.

An annoyed expression.

Messy, long, raven hair.

Sharp features.

Loki.

Oh great, just what she needed.

(Y/N) let a pulse of her energy out into his hands, and he let out a yell, before responding with his own magic, binding her energy slowly, and (Y/N)’s eyes flew wide open.

“Oh hell no.” She muttered, and lashed out with her foot, kicking him square in the nuts.

His face twisted up in agony and she grinned at how his face crumpled to form a sort of lemon-induced expression that only she found funny.

He didn’t let go though, he only hunched over, his magic still flowing into her core, binding her abilities, and every time she healed her core, every time she peeled off a part of his magic, he would respond by pulling his binds tighter.

“Hurry up, I can’t hold her for long.”

“You’re a master magic-wielder, and you’re our prisoner, you will hold her as long as we want you to.” Stark’s voice broke through (Y/N)’s mind and she let out as much energy as she could without killing anyone and without draining herself.

Loki screamed, a deep throaty sound, not high-pitched and pain-induced, more anger and frustration that he had been bested.

(Y/N) leapt back and realised she was surrounded, above and behind.

“Don’t move, kid.” Tony said, pointing his Iron Man glove at her, and she suddenly realised that the Black Cross on her chest had been ripped off at some stage, and her mask was down.

“That’s no kid.” Loki spoke through gritted teeth, massaging his hands and glaring daggers at (Y/N), but still watching appreciatively. Not many could best him in a battle of magic. “That’s an Ether. They are creatures of the Reality and Shadow. They can manipulate how something is fixed, how something is broken, they can turn back time on objects and reverse what has happened. They are keeping the balance between worlds, and they are the only things that could stand a chance against the Infinity Stones. This one is the Ether of Death.” He snarled at her, and she flinched.

“As far as I know, I’m a human. As far as you guys know, I’m the Black Cross. And as far as anyone knows, I was never here and I am getting out of here now.” She sped off, using her enhanced speed to go faster than light, then slowing down to just slower than sound so that she would be more difficult to track without the sonic boom she left behind.

Loki appeared in front of her and lifted her up again, this time with magic. She was trapped in an orb of green energy. “Not so fast, little one.” He hovered the orb in front of him as they travelled back towards the base. “I must know, who were you here to kill? No one has died so far. And as the Ether of Death, I was thinking you’d just kill them from a distance.”

“Okay, first of all, Asgardian beanstalk, I don’t just kill people after getting an assignment, I evaluate if the person is worth the effort, if they would be better dead or living. I was sent to kill Tony Stark because he keeps on sleeping with the crazies and they just want him dead. I have morals, unlike some people I know. Second of all, I only just found out I was the Ether of Death from you. As far as I knew, I could only heal people and pull them apart. Third of all, I have absolutely no aim with any sort of projectile.” (Y/N) told him sourly, crossing her arms and pouting, pulling her hood back up so that she had her Black Cross symbol on her forehead. “And third of all, I’m a seasoned assassin, if you hadn’t been here as the god of mischief and magic-wielder, then I would never have been found, so you better bet that pretty little ass of yours that I will get my sweet, sweet revenge.” She regretted every word.

“Pretty little ass? You like my ass?” Loki asked, amused, and (Y/N) rolled her eyes, but couldn’t stop the blush that crept up her neck and dusted her cheeks. Thank goodness she had her mask on.

“Yeah.” She mumbled, and Loki cackled.

“What was that? I couldn’t hear you?” He mocked her, and she glared at him. Pulling off her glove, she placed her bare hand on the green orb and dove into it with her energy, pulling part of her consciousness into it as well, she felt herself surge through his energy and directly to his core.

She began to touch and poke at his core, noting how her touch made his core shiver.

“Stop.” He commanded, and she continued. Her vision was getting blurry and doubled, she could see a concerned Loki, but she could also see his energy. It was so pretty and green, pure green, swirling and mixing.

She poked it again, and Real Loki flinched, clutching at his chest.

“Please?” He tried again, and she withdrew slowly, scraping her energy into whatever there was on the way back to her body. He looked at her, slightly fearful, but more curious than anything else. “What are you?”

“Well, I was recently told by an asshole trickster god that I’m the Ether of Death.” (Y/N) shrugged nonchalantly, and Loki let a bark of laughter out.

“I was mistaken; you are the Ether of Life Energy.”

“What’s the difference?” (Y/N) asked as the Compound became visible again. She turned her back to him and watched as the Avengers came into view, all looking pretty pissed.

“Life energy means you can manipulate how long a person lives, how a person lives and what sort of energy they can use from their magical core. Death just means you can prolong a person’s life, or shorten it.”

“They’re the same thing.”

“Nearly. Life energy has an element of magic.” Loki’s eyes had lit up, meaning that this was probably a subject he enjoyed talking about, but they dimmed again when the Avengers approached them.

Tony was the first person to speak after seeing (Y/N) with her mask on. “Well… who’d have thought the infamous Black Cross assassin was really a kid in black clothing?”

“Me.” (Y/N) responded immediately.

“Yeah, but you knew.” Tony argued.

“True.” (Y/N) shrugged. “So what are you going to do with me? Send me to the Raft? Kill me? Destroy my mind, body and soul?” She asked, genuinely curious, and pulled her hood back. She had an innocent mask on and was thoroughly enjoying watching them squirm.

“Of course not,” Steve started, taking the calm, fatherly-figure approach, “we would never do such a monstrous thing.”

“Really?” (Y/N) asked innocently, but there was a glint in her eyes that warned him that his next answer would be a trap.

“No.” He either saw the warning, and still answered with the same thought, or wasn’t observant enough and was willing to cling to his own thoughts.

“So you’re just going to let a little girl, who’s killed more people than there are days in a year, roam freely?” (Y/N)’s eyes had been altered slightly, just enough for her expression to go from curious to creepy.

“No, we’re going to keep the little girl who actually isn’t all that guilty tied to our sides for the rest of her life. I think that’s punishment enough.” Steve responded, his voice hard. “If you did do what you told Loki, then you know what’s good for you.”

(Y/N) glanced back at Loki, who pulled a little electronic device out of his tunic and threw it to Tony, who caught it easily and went on to fidget with it.

“It’s better than nothing.” (Y/N) shrugged. “Besides, when more customers come looking for my services and I refuse them, then I have somewhere to kill them in peace without any public authorities calling for my head.” She gave Steve a vicious smirk, and Steve raised an eyebrow.

“Thor, tell your brother to let her go.” Steve told Thor without looking up.

“You can just address me directly, Captain.” Loki growled, but let (Y/N) go, and she landed in a heap, before getting up quickly and glancing around to see everyone with at least one weapon drawn.

She sighed as if defeated raising her hand in a placating manner, then as soon as their guards dropped, she sprinted around and grabbed all their weapons, dumping them at her feet, and picking them up one at a time, inspecting them quickly.

Loki was the only one who had remained untouched and she grinned as she found a particularly good blade she had stolen from Natasha.

“Can I keep it?” She asked Loki directly, and he hid his surprise, but was confused as to why she was asking him, not the owner.

“How did you do that?” Tony caught on as soon as Loki gave her a miniscule nod and a predatory glint appeared in her eyes as she quickly crouched on top of the pile as if it were her dragon hoard.

“Y’know, super speed and stuff.” (Y/N) told him pleasantly, and he sighed.

“We should get you presentable when you inevitably meet Fury.” He sighed, in an almost defeated manner. (Y/N) glanced towards Loki, the only one she had truly interacted with.

He made a shooing gesture, and she didn’t budge, obviously wanting something else.

“Fine, Loki will come too, but neither of us are supervising you as you get changed.” Tony responded. “Besides, if you have the hots for Loki, then I can tell you now, he’s a handful.”

“Good thing I have two hands.” (Y/N) retorted quickly as heat rose through her cheeks. Tony rolled his eyes.

“Well, you’ll get time to win him over later, but now, you need to get cleaned up.”

“Okay.” She let her energy out in a pulse, the dried blood crackling and falling off her as she shook her body out, then she pulled the ninja outfit off to reveal civilian clothing. Folding her little costume over her arm and looking to Tony, who was just baffled, before looking back to Loki, who was amused, before getting bored and poking Tony in the cheek.

“And you always wear civilian clothing underneath your suit?”

“Yeah, it makes a good disguise, and usually I have a backpack hidden nearby to the target’s living quarters so I have somewhere to stuff it.” (Y/N) responded. “I’ve been doing this for a year or so, I have a system.”

“I don’t doubt it, kid.” Tony told her, before guiding her around the building. “So, I guess you’ll be staying in the guests’ suite?” He seemed to say it like a question, but then was answered.

A deeper voice had seemed to take over and (Y/N) whirled around, immediately on high alert. “No, she’ll be coming with me for now and then I’ll return her to you.”

“I don’t think so.” Loki said smoothly, gliding into the conversation as if he had always been there, instead of just trailing after them.

“And what makes you think you have a say in this?” Fury asked Loki with a deadpan expression.

“I think I have a say in this because she’s my charge now. As the Ether of Life Energy, I believe I would best guide her in her energy manipulating abilities.” Loki said without glancing back at (Y/N), and she was impressed that he had thought of the reason almost immediately. But she was slightly concerned, because she honestly didn’t want to learn about how she could destroy someone’s life span and change someone’s life with just the smallest nudge. That didn’t sound too fun.

“But she will be staying at this facility, and she will not leave the facility. Ever.” Fury snapped, and (Y/N) internally groaned. She absolutely hated getting restricted.

“That will be easily managed.” Loki responded slyly, and Fury narrowed his one eye, but said nothing and dramatically left the room.

“What did you do to Fury?” Tony immediately turned on Loki, and Loki smirked.

“It seems your precious Director still seems to be slightly scared of what I can do, and what I could do if I had control of the Ether of Life Energy, or he may be more scared of what the Ether of Life Energy and the God of Mischief could do together if they were displeased.” Loki told him cheekily, and (Y/N) rolled her eyes.

“As if you’d control me.” (Y/N) told him. “I bet you wouldn’t even be able to make me shut up.”

“Shut up.” Loki commanded.

“Make me.” (Y/N) stated in an almost bored tone, and with two steps, Loki had her trapped against the wall, his lips centimetres from hers.

Her breathing hitched at his close proximity, his entire body was pressed against hers, and his face showed nothing but smugness.

(Y/N) scowled, determined not to lose this challenge and grabbed his hips, before deftly spinning them around and pinning him against the wall, pressing her weight against him, and Tony cleared his throat behind them.

“I’ll be down at the workshop if you want to find me after you fix this… sexual tension.” He told them calmly, before disappearing, and (Y/N) flushed red.

“Oh how easily you blush.”

“Oh how easily you bleed.” (Y/N) hissed at him, her hands tightening to an almost bruising level, and he simply smirked.

“You think you’ve got the upper hand.” Loki placed his hands on her shoulders, and a split second before she could react (she was busy thinking about what his lean, muscled body felt like underneath hers) and had her pinned against the wall, his lips on hers.

Dam. That was her only thought. His cold lips moved perfectly against her own warm ones, and one of his hands snaked around her neck to cradle her head.

His tongue poked at her lips, and she parted them slightly, before realising exactly what silver-tongue meant. Knees weak, and hands splayed against the wall behind her in an effort not to give in, she bit his lip sharply, and he drew away almost immediately, gaze heated and hand on his lip.

“Feisty.” He said with amusement in his eyes before taking a step back. She immediately missed the close proximity that made her feel trapped but secure.

“Bold.”

“Aggressive.”

“Says the one that tried to take over New York.”

“Touché.” He muttered, before glancing at her lips again. “May I?” He asked tenderly, this time his facial expression had softened, and whilst she was still on edge, still wary of what sort of trick he would spring on her the minute she let her guard down, she vaguely felt herself nodding, and his lips lightly connect to hers. It wasn’t like the other one, it wasn’t biting and asserting dominance, it was more… soft.

Just soft.

Everything was soft.

His lips.

His hands.

His grip on her body.

The only thing that was hard was her grip on the collar of his tunic, pulling him down and trying to deepen the kiss.

“Ahem, brother. I need you for a minute, so if you could please leave your lady’s lips for one moment, could I please talk to you about something?” Thor’s rumbling voice interrupted them, and (Y/N) looked down, embarrassed to be caught so vulnerable.

She could see his lips twist up in a snarl, and he stormed away with Thor, but not before he turned around to point at (Y/N) teasingly saying, “I’m not done with you yet.”

What the hell just happened?


End file.
